I haven't tried $20 claude code recently, but I've used OpenCode Zen primarily so I can play with opensource/chinese models which are very inexpensive. I'd spend $0.50-$1.00 on a single claude opus 4.6 plan mode run, then have a chinese model execute the plan for like $0.10-$0.15 total. I'd keep context short, constantly start new threads, and get laser focused markdown plans and knowledgebase to be token efficient.

If I just let opencode zen run claude opus to plan and execute, I'd spend $20 in like 5 minutes lol